Cam layout device



Jan. 3, 1967 P. A. GREIDER 3,295,212

CAM LAYOUT DEVICE Filed July 2, 1964 2 Sheets-Sheet 1 IN VEN TO'R.

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flrra elvfys United States Patent 3,295,212 CAM LAYOUT DEVICE Paul A. Greider, Dayton, Ohio, assignor to Dayton Perforators, Inc., Dayton, Ohio, a corporation of Ohio Filed July 2, 1964, Ser. No. 379,798 Claims. (CI. 3327) This invention relates to the preparation of cam blanks for machining, and particularly to apparatus and methods for scribing a cam profile on a cam blank.

The object of the invention is to simplify the construction as well as the means and mode of operation of cam layout devices, whereby such devices may not only be economically manufactured, but will be more eflicient and satisfactory in use, adaptable to a wide variety of application, and be unlikely to get out of order.

A further object of the invention is to obviate the need for separate layout with subsequent transfer of profile to a cam blank prior to cut-out.

Another object of the invention is to enable a machinist, or one relatively unskilled in the art of calculating and formulating cam design, to lay out a cam profile on a cam blank.

A further object of the invention'is to provide a generally new device through the use of which a cam profile can be scribed directly on a cam blank, with no intermediate design step.

Still another object of the invention is to introduce a new method of cam layout offering the advantages above indicated.

A further object of the invention is to provide devices possessing the advantageous structural features, the inherent meritorious characteristics and the mode of operation herein mentioned.

With the above and other incidental objects in view as will more fully appear in the specification, the invention intended to be protected by Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter de scribed or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing wherein is shown one but obviously not necessarily the only form of embodiment of the invention,

FIG. 1 is a view in perspective of a cam scribing device in accordance with the illustrated embodiment of the apparatus of the invention;

FIG. 2 is a view in side elevation of the device of FIG. 1;

FIG. 3 is a plan view of the scriber device of FIGS. 1 and 2 applied to a cam blank; and

FIG. 4 is a view in perspective of a cam blank bearing scribe marks as produced by the scribe device.

Like parts are indicated by similar characters of refence throughout the several views.

Referring to the drawings, apparatus of the invention, in accordance with the illustrated embodiment, comprises a body of elongated generally rectangular shape. One broad side 11 of the body 10, which may be considered the underside thereof, is flat to lie flush against a cam blank. A circular boss or tenon 12 is fixed to the body 10 in an overlying projecting relation to the flat surfaced side 11. On the opposite side of the body 10, and opening through one end thereof, is a groove 13 of longitudinal extent. Reciprocable in the groove 13 is a slide member 14 having one end in a projected relation to the body 10. Side plates 15 and 16 are fastened to what may be considered the top side of the body 10 or that side opposite fiat underside 11. The plates are installed slightly to overlap adjacent respective side edges of the groove 13 whereby to achieve a confining relation to the slide member 14.

A stationary abutment member 17 is secured to the body 10, to the said top side thereof, in a superposed relation to the side plates 15 and 16, and projects laterally from the body in a generally opposed relation to the tenon 12. The abutment member 17 is disposed intermediate the ends of the body 10 and has a longitudinal through opening, screw threaded for mating engagement with a screw post 18. One end of the post 18 extends through and beyond what may be considered the bottom of abutment 17. At the opposite end of the post is an integrally formed knurled nut 19 adapted for thrust engagement on its underside with a reactant member 21 secured to the projected end of the slide member 14. The reactant member 21 projects laterally of the scribe device in the same direction as abutment member 17 with respect to which it is in an overlying spaced relation.

The abutment member 17 also receives one end of a cylindrical tube 22 which at its opposite end projects substantially beyond what may be considered the lower end of the body 10. By reason of its elongated character the tube 22 accommodates extending and retracting movements of a stem 23 and also is adapted to serve as a'handle for the scribe device. The tube 22 and stem 23 are part of a gaugeassembly further comprising a gauge device 24 anchored through a tongue 25 and pin 26 to the lower end of body 10. The tube 22 passes through the body of the gauge 24 while reciprocable stem 23 is connected in a manner which it is unnecessary here to consider to an indicator needle 27 movable over a dial 28 of the gauge. The dial is calibrated in a suitable manner, as for example in gradations of hundredths of an inch to indicate by the movement of needle 27 the extent of travel of stem 23.

The latter element projects through and beyond that end of tube 22 received in abutment member 17. The projected end of the stem is formed with a head 29 adapted to engagethe underside of reactant member 21 or the side opposite that engaged by the screw post nut 19. The needle 27 and connected stem 23 are stressed, as by spring means, to occupy normally a predetermined position, such stressing being applied to the stem 23 in a direction to urge it outward or toward engagement with the reactant member 21. A knurled external knob 31 on the gauge 24 allows for adjustment of the needle 27 independently of the stem 23.

At its upper end the slide member 14 is formed with a head portion 32 enlarged in the direction of the fiat under surface 11 of the body 10. A pointed instrument or scribe 33 is mounted in the head 32 with the point thereof lying substantially in the plane of surface 11. An adjusted position of the slide member 14 is adapted to be maintained by a set screw 34 mounted in the side of body 10 to have the inner end of its shank portion project into the slot 13 from the side thereof. There the screw device is adapted to achieve a clamping or releasing relationship to the slide member 14 whereby-the member may alternatively be held to an adjusted position or released for movement to another adjusted position.

A scribe device as disclosed is adapted for use with cam blanks, for example a cam blank 35 as shown in FIGS. 3 and 4. There the blank has the form of a fiat circular disc in the center of which is a through opening 36. One of the flat sides or surfaces of the disc may be formed with a circumferential series of radially inscribed lines 37, the distance between adjacent lines representing some selected or predetermined angular part of a circle. In the use of the device it is placed with the flat underside 11 flush against the flat surface of the cam disc, with tenon 12 received in the opening 36. So positioned, the scribe device is capable of rotary motion relative to the cam blank but is precluded from any bodily shifting motion in a lateral sense, From prepared calculations the extent of the rise or fall of the cam surface is determined, as well as the length of the circle segment within which such rise or fall takes place. With these facts known slide member 14 is adjusted outwardly of the body to locate the scribe 33 at a point of an extreme diameter, for example to the .position of largest diameter. The device is then rocked about the tenon 12 to make a short arcuate mark on the cam blank surface with scribe 33. Following this, in a successive series of steps, the slide member 14 is adjusted inward a distance which is an increment of the total rise or fall of the cam surface and the scribe device again rocked in a succeeding radial plane to make another arcuate mark on the cam blank, these actions being repeated until the smallest cam diameter is reached. With the scribed device removed from the cam blank the several scribed points are then joined with a french curve to generate a solid profile line After all the required lobes have been plotted in their correct positions on the cam a conventional cut down template is used to complete the cam profile and the blank is ready for machining.

Considering the slide member 14 as having extending and retracting motions relative to body 10, extending motion thereof is limited by engagement of reactant member 21 with the nut 19 of screw post 18. The latter is accordingly suitably adjusted to allow initial positioning of the slide member as above described. The stem 23 has the character of a spring pressed plunger in a following relation to reactant member 21 and slide member 14 of which it is a part. An extending motion of the slide member 14 outward to locate scribe 33 at the position of largest cam surface diameter is thus followed by stem 23, with a consequent related rotary motion of needle 27. The repeated increments of retracting movement of the slide member 14, to move the scribe 33 from one marking position to another, is accomplished by rotational adjustment of the head 19 of screw post 18, the gauge 24 being observed to insure accuracy and uniformity of the incremental adjustment movements. According to one possible method of operation, after the scribe 33 has been located at the position of largest diameter, the gauge 24 is set by hand, through knob 31, to a zero position. Subsequent adjustments, though manipulation of nut 19, are reflected in an incremental advance of needle 27 over the dial 28, with the series of adjustments being completed upon arrival of the needle at a predetermined reading. In the use of a cam blank marked with the lines 37 of angular definition these lines may conveniently be spaced in hundredths. Successive arcuate marks are made to intersect with successive lines 37. Incremental adjustments of the head 19 may under this condition be predetermined according to a formula by which the total rise ofthe cam surface is divided by the number of hundredths in the angle of the selected cam surface. For example, if the rise is onehalf inch and is to be made within one tenth or thirty-six degrees of the cam blank, prior to moving to each successive line 37 the gauge stem 23 is thrust inward or compressed by adjustment of head 19 a distance to effect a change in reading of .050 on the dial 28.

The cam blank of FIG. 3 is shown inscribed with separate series of scribe marks 38 and 39 representing different defined lobes. Similar series of marks 41, 42. and 43 on the cam blank of FIG. 4 show different described lobes.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of' advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one A of several modes of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described my invention, I claim:

1. A unitary scribe device to lay out a cam profile on a cam blank, including a body having a flat underside to lie flush on a cam blank surface, said body having a longitudinal groove therein, a slide member in said groove extensible and retractable relatively to said body, an outer projecting end of said slide member having scribe means dependent to said underside of said body, abutment means on the opposite or upper side of said body, a tube installed in said abutment means and disposed longitudinally of said body, said tube projecting relatively beyond said body to one end, a screw post having a threaded engagement in said abutment means and extending longitudinally of said body in a direction opposed to said one end of said tube to have one end thereof project relatively to said body in a direction remote from said one end of said tube, manipulative head means fixed to said one end of said screw post, a reactant member fixed to said slide member and projecting therefrom oppositely to said scribe means, said screw post passing through said reactant member, a spring biased stem slidably received in the other end of said tube projecting therefrom to engage said reactant member in an opposing relation to said manipulative head means to compel a following movement of said slide member with respect to said manipulative head member, an indicator gauge mounted on said tube in a connected relation to said stem, and a tenon on the said underside of said body to be received in the center opening of a cam blank, said device being rotatable about said tenon as a pivot, the said one end of said tube being accessible at one end of the device as a handle for rotary movement of the device as a unit, said manipulative head means being accessible at the other end of the device for individual longitudinal adjustment of said slide member by pressure thereon through said reactant member.

2. A unitary scribe device according to claim 1, characterized in that said abutment means and said reactant member are in an upstanding projecting relation to the upper side of said body, said screw post being in an interconnecting relation thereto and in a relative underlying relation to said tube and its projecting stem.

3. A unitary scribe device to lay out a cam profile on a cam blank, including a body, a slide member extensible and retractable in said body in opposed longitudinal senses, said slide member having an inner end received in said body and an outer relatively projected end, a scribe mounted to said outer end, a reactant member fixed to and projecting from said slide member, separate means for applying opposing thrusts to said slide member through said reactant member, said separate means including screw ost means threadedly mounted in said body and having a portion engaging said reactant member on one side thereof to move said slide member in one of said longitudinal senses and further comprising rod means on said body engaging said reactant member on an opposite side and urged resiliently to maintain said reactant member in engagernet with the said portion of screw post means, said screw post means and said rod means cooperating longitudinally to position said slide member, a gauge on said body in a connected rela tion to said rod means, and means on said body adapt-ed to be received in a center opening in a cam blank and form a joint therewith for rotary adjustment of said body and mounted parts.

4. A unitary scribe device according to claim 3, characterized in that said body has a generally rectangular shape providing a flat underside to lie flush against a cam blank, the scribe on said slide member projecting in one direction from said slide member substantially at the plane of said fiat underside, and said reactant member projecting oppositely, said joint means being on the said flat underside of said body.

5. A unitary scribe device to lay out a cam profile on a cam blank, including a body, said body having a flat underside to lie flush upon a cam blank and having projecting from said underside a tenon to be received in said cam blank and provide for relative rotary movement of said body, said body having a slideway disposed therein and opening through one edge portion thereof, a slide member received in said slideway to move longitudinally thereof, one end of said slide member projecting through and beyond said one edge portion of said body, a scribe mounted on said one end of said slide member and dependent therefrom to the underside of said body, an abutment member mounted on the top side of said body in transverse relation to said slideway, a tube mounted at its one end in said abutment member and extending therefrom in a sense opposite to the projection of said slide member, a gauge mounted in an upstanding projecting relation to the top side of said body, said tube passing through said gauge and projecting therebeyond to present a portion serving as a handle which may be grasped for manually rotating said body around said tenon as a pivot, a reactant member upstanding on said one end of said slide member in a parallel spaced relation to said abutment member, a screw post having a threaded mounting in said abutment member and extending through and beyond said reactant member, a head on the projecting References Cited by the Examiner UNITED STATES PATENTS 1,133,585 3/1915 Simons 33-189 1,700,496 1/ 1929 Heitzler.

1,981,713 11/1934 Swenson 33-174 2,285,918 6/1942 Farrar 33-189 X 2,376,038 5/1945 Dawson 33-147 2,447,612 8/1948 Dowe 33-147 2,691,825 10/1954 Pearson 33-147 OTHER REFERENCES Publication: American Machinist, Dial Attachment for Calipeis Aids Inspectors, April 25, 1946, page 136.

LEONARD FORMAN, Primary Examiner.

ISAAC LISANN, Examiner.

H. N. Haroian, Assistant Examiner. 

1. A UNITARY SCRIBE DEVICE TO LAY OUT A CAM PROFILE ON A CAM BLANK, INCLUDING A BODY HAVING A FLAT UNDERSIDE TO LIE FLUSH ON A CAM BLANK SURFACE, SAID BODY HAVING A LONGITUDINAL GROOVE THEREIN, A SLIDE MEMBER IN SAID GROOVE EXTENSIBLE AND RETRACTABLE RELATIVELY TO SAID BODY, AN OUTER PROJECTING END OF SAID SLIDE MEMBER HAVING SCRIBE MEANS DEPENDENT TO SAID UNDERSIDE OF SAID BODY, ABUTMENT MEANS ON THE OPPOSITE OR UPPER SIDE OF SAID BODY, A TUBE INSTALLED IN SAID ABUTMENT MEANS AND DISPOSED LONGITUDINALLY OF SAID BODY, SAID TUBE PROJECTING RELATIVELY BEYOND SAID BODY TO ONE END, A SCREW POST HAVING A THREADED ENGAGEMENT IN SAID ABUTMENT MEANS AND EXTENDING LONGITUDINALLY OF SAID BODY IN A DIRECTION OPPOSED TO SAID ONE END OF SAID TUBE TO HAVE ONE END THEREOF PROJECT RELATIVELY TO SAID BODY IN A DIRECTION REMOTE FROM SAID ONE END OF SAID TUBE, MANIPULATIVE HEAD MEANS FIXED TO SAID ONE END OF SAID SCREW POST, A RECTANT MEMBER FIXED TO SAID SLIDE MEMBER AND PROJECTING THEREFROM OPPOSITELY TO SAID SCRIBE MEANS, SAID SCREW POST PASSING THROUGH SAID REACTANT MEMBER, A SPRING BIASED STEM SLIDABLY RECEIVED IN THE OTHER END OF SAID TUBE PROJECTING THEREFROM TO ENGAGE SAID REACTANT MEMBER IN AN OPPOSING RELATION TO SAID MANIPULATIVE HEAD MEANS TO COMPEL A FOLLOWING MOVEMENT OF SAID SLIDE MEMBER WITH RESPECT TO SAID MANIPULATIVE HEAD MEMBER, AN INDICATOR GAUGE MOUNTED ON SAID TUBE IN A CONNECTED RELATION TO SAID STEM, AND A TENON ON THE SAID UNDERSIDE OF SAID BODY TO BE RECEIVED IN THE CENTER OPENING OF A CAM BLANK, SAID DEVICE BEING ROTATABLE ABOUT SAID TENON AS A PIVOT, THE SAID ONE END OF SAID TUBE BEING ACCESSIBLE AT ONE END OF THE DEVICE AS A HANDLE FOR ROTARY MOVEMENT OF THE DEVICE AS A UNIT, SAID MANIPULATIVE HEAD MEANS BEING ACCESSIBLE AT THE OTHER END OF THE DEVICE FOR INDIVIDUAL LONGITUDINAL ADJUSTMENT OF SAID SLIDE MEMBER BY PRESSURE THEREON THROUGH SAID REACTANT MEMBER. 